by Susan Page, USA TODAY

by Susan Page, USA TODAY

WASHINGTON - Ratings of the GOP match historic lows in a new USA TODAY/Pew Research Center Poll, but Republican voters are more optimistic than Democrats about how their party is going to fare in next year's congressional elections.

Analysts are watching for signs of whether a "wave" election might be in the works, the sort of lopsided outcome that could boost Republican efforts to win control of the Senate or even longer-shot Democratic dreams of regaining the House.

The new survey, taken Dec. 3-8, shows a conundrum: Democratic congressional leaders rate higher and registered voters by 48%-44% say they would vote for the Democratic congressional candidate in their district over the Republican if the election were held today.

At the same time, by 53%-47% Republican voters are more likely than Democrats to say they are "very enthusiastic" about voting in 2014 â?? a key test of whether they'll bother to go to the polls. And they predict better results for their party next year, another poll question that in the past has signaled the elections that follow.

A 55% majority of Republicans and voters who lean to the GOP say Republicans candidates will do better next year than they have in recent elections; 33% say they will fare about the same.

In contrast, Democrats and Democratic-leaning voters split 43%-43% over whether the Democratic Party will do better or about the same as in recent years.

Very few in either party predict things will get worse: Just 5% of Republicans and 9% of Democrats.

White House travails are fueling Republicans' expectations, says James Campbell, a political scientist at Syracuse University and author of The American Campaign: U.S. Presidential Campaigns and the National Vote.

"President Obama is on the defensive," Campbell says, with even support among some liberals fraying. "When you see that softening on the other side, it gives some encouragement to Republicans. Now, they can certainly get overly optimistic, and you can't discount the possibility of Tea Party-establishment warfare grabbing defeat from the jaws of victory. But right now it looks pretty promising for Republicans."

He doesn't see the ingredients, at least not yet, for a sweeping "wave" election, however. While there is an expectations gap between Republican and Democratic voters, it isn't as wide as it was before the 2010 elections, when Republicans by a huge margin predicted victories, or before the 2006 midterms, when Democrats were overwhelmingly confident.

In 2010, Republicans regained control of the House. In 2006, Democrats won back the Senate.

Next year, the GOP needs a net gain of six Senate seats to win control. In their favor: Democrats are defending 21 of the 35 seats that are up, including six in states that Republican Mitt Romney carried in 2012.

That said, the standing of the Republican Party and Republican congressional leaders has never been lower. Fifty-nine percent of those surveyed have an unfavorable view of the GOP, tied for the highest negative rating ever. What's more, 28% feel strongly about it, saying they have a "very unfavorable" view.

Seventy-two percent disapprove of Republican congressional leaders, also matching the historic high. Approval of GOP congressional leaders hasn't risen above 25% the last 10 times Pew has asked the question, going back to July 2011.

Democrats don't fare well, but they do better than that. Those surveyed approve of Democratic congressional leaders by 34%-58%. Forty-eight percent have an unfavorable view of the Democratic Party; 24% say they have a "very unfavorable" view.

The poll of 2,001 adults, taken Dec. 3-8, has a margin of error of +/- 3 percentage points.